1. Field of the Invention
The present invention relates to a capacitor element, a semiconductor integrated circuit having a pair of mutually overlapping interconnection layers, and a method of manufacturing those. In particular, the present invention relates to a capacitor element structure, which can readily achieve large capacitances, and a method of manufacturing the same.
2. Description of the Related Art
A semiconductor integrated circuit is integrated with resistors and capacitor elements in addition to active elements such as transistors. There has been known a conventional capacitor element disclosed in Japanese Patents No. 3307342 and No. 3193973. The capacitor element disclosed in the foregoing Patents has the structure in which a dielectric layer is sandwiched between a pair of metal plates. In the capacitor element having the foregoing structure, the large capacitance is achieved to slim of the dielectric layer.
In addition, Japanese Patents No. 3209253 discloses a conventional capacitor element having the following structure. According to the structure, a pair of metal layers is arranged on the identical surface, and comb-shaped portions of the metal layers are overlapped with each other via a dielectric layer. In the capacitor elements having the foregoing structure, the large capacitance is achieved in the following manner. More specifically, the minimum dimension of the distance between the metal layers is made small, and the surface area of mutually overlapping comb-shaped portions is increased.
However, slimming of the dielectric layer and the minimum dimension of the distance between the metal layers are reaching the limit with the advance of process. For this reason, it is difficult to achieve the large capacitances.